src/cpu/s390/vm/macroAssembler_s390.hpp

*** 438,450 ****
    address get_PC(Register result);
  
    // Get current PC + offset. Offset given in bytes, must be even!
    address get_PC(Register result, int64_t offset);
  
    // Resize current frame either relatively wrt to current SP or absolute.
    void resize_frame_sub(Register offset, Register fp, bool load_fp=true);
!   void resize_frame_absolute(Register addr, Register fp, bool load_fp=true);
    void resize_frame(RegisterOrConstant offset, Register fp, bool load_fp=true);
  
    // Push a frame of size bytes, if copy_sp is false, old_sp must already
    // contain a copy of Z_SP.
    void push_frame(Register bytes, Register old_sp, bool copy_sp = true, bool bytes_with_inverted_sign = false);
--- 438,462 ----
    address get_PC(Register result);
  
    // Get current PC + offset. Offset given in bytes, must be even!
    address get_PC(Register result, int64_t offset);
  
+   // Accessing, and in particular modifying, a stack location is only safe if
+   // the stack pointer (Z_SP) is set such that the accessed stack location is
+   // in the reserved range.
+   //
+   // From a performance point of view, it is desirable not to change the SP
+   // first and then immediately use it to access the freshly reserved space.
+   // That opens a small gap, though. If, just after storing some value (the
+   // frame pointer) into the to-be-reserved space, an interrupt is caught,
+   // the handler might use the space beyond Z_SP for it's own purpose.
+   // If that happens, the stored value might get altered.
+ 
    // Resize current frame either relatively wrt to current SP or absolute.
    void resize_frame_sub(Register offset, Register fp, bool load_fp=true);
!   void resize_frame_abs_with_offset(Register newSP, Register fp, int offset, bool load_fp);
!   void resize_frame_absolute(Register newSP, Register fp, bool load_fp);
    void resize_frame(RegisterOrConstant offset, Register fp, bool load_fp=true);
  
    // Push a frame of size bytes, if copy_sp is false, old_sp must already
    // contain a copy of Z_SP.
    void push_frame(Register bytes, Register old_sp, bool copy_sp = true, bool bytes_with_inverted_sign = false);
*** 459,468 ****
--- 471,482 ----
    // Push a frame of size `bytes' with abi160 on top.
    unsigned int push_frame_abi160(unsigned int bytes);
  
    // Pop current C frame.
    void pop_frame();
+   // Pop current C frame and restore return PC register (Z_R14).
+   void pop_frame_restore_retPC(int frame_size_in_bytes);
  
    //
    // Calls
    //